The carefully crafted House Budget Committee compromise balancing the fiscal 1981 budget hit an embarassing snag yesterday over a procedural issue, forcing postponement of scheduled floor action on the measure.

The hitch came as liberals and some Republicans on the budget panel protested a 13th-hour decision to change the accounting procedures used in last week's compromise to show a surplus of $5.5 billion instead of $2 billion as indicated previously.

Reaction from panel members was so strong that Budget Committee chairman Robert N. Giaimo (D-Conn.) decided to cancel plans to begin floor debate on the resolution this Friday, and instead reconvened the committee for Wednesday.

Meanwhile, committee sources reported flat-out opposition from chairmen of several key House authorizing committees on a provision in the budget measure that would require their panels to make program cuts to meet the new spending targets.

It was not immediately clear how serious the flap over the surplus figure would prove. Giaimo was expected to try to resolve it on Wednesday by reverting to the $2 billion number, but the outcome still was uncertain.

However, congressional figures expressed fears that the other flap, involving the authorizing committees, could seriously hamper efforts to balance the budget. The panel had been counting on its requirement as a disciplinary tool.

The series of developments sparked a round of high-level meetings between Giaimo and House majority leader Jim Wright (D-Tex.) and groups of key Democrats and Republicans on the panel.

There were fears in some quarters that if the $5.5 billion surplus figure were retained, liberals might seek to use the extra as a lever to add more money for domestic programs.

The panel voted last week to cut $16.5 billion in spending from the reestimated version of Carter's January budget. Liberals' efforts to reduce the cuts in social programs were soundly defeated.

The difference between the two surplus figures involves the way a proposal the panel added to the budget resolution is counted. The proposal would require the House Ways and Means Committee to raise $3.5 billion in new revenues to help ease the fiscal burden.

The panel originally intended to place the $3.5 billion in a special contingency fund -- along with $10.3 billion in revenues from Carter's new oil-import fee -- to be used for eventual tax cuts.

However, in its deliberations last week, the committee voted in a late-night session to count only the $10.3 billion from the oil-import fee toward a tax cut. The $3.5 billion was essentially left in limbo, with the surplus at $2 billion.

On Friday, the committee announced formally that the $3.5 billion would be counted as part of projected tax revenues, automatically boosting the surplus the panel was projecting to $5.5 billion because of the change.

A survey of panel members late yesterday showed mixed reactions to the shift, with some lawmakers merely waiting to see what happens before publicly taking sides in the dispute.

Sources said Giaimo most likely will try to handle it simply by asking the committee to rescind its recommendation that Ways and Means raise an extra $3.5 billion in new revenues, thereby cutting the surplus back to $2 billion.

The $2 billion surplus does not include the impact of the president's new oil-import fee, which raises $10.3 billion in new revenues. With that measure accounted for, the surplus actually is $12.3 billion.

However, Giaimo and other senior Democrats insisted on not counting the $10.3 billion to increase pressure on the House to approve the proposed spending cuts. Carter has proposed a similar accounting maneuver.

Meanwhile, House liberals were reported trying to put together a proposal for a floor amendment that would reduce the committee's $16.5 billion in spending cuts by several hundred million dollars.

There were some indications the liberals may try to prod the budget panel into adopting them at the meeting on Wednesday. House leaders want the liberals' support to bolster prospects for the budget resolution's passage.

Rep. David Obey (D-Wis.), leader of the committee's liberal bloc, met privately yesterday with Wright and representatives of the AFL-CIO to try to work with out a compromise, but declined later to talk about the liberals' plans.

However, the liberals were reportedly split yesterday over how far to go in trying to amend the Budget Committee proposal. Some were said to be pressing for a full-fledged substitute for the panel's resolution.